Binder jetting is an additive manufacturing technique based on the use of a liquid binder to join particles of a powder to form a three-dimensional object. In particular, a controlled pattern of the liquid binder is applied to successive layers of the powder in a powder bed such that the layers of the material adhere to one another form a three-dimensional green part. Through subsequent processing, the three-dimensional green part can be formed into a finished three-dimensional part.
A binder jet fabrication system may comprise at least a printing subsystem, a build box (also known as job box) subsystem, a de-powdering subsystem and a sintering oven. The build box subsystem may comprise a powder print bed with a constituent object therein. In operation, the build box may be moved through the binder jet fabrication system, to be sequentially associated with other subsystems of the binder jet fabrication system.
In the case of more than one object within one build box, the objects may be vertically stacked to form a print bed stack of nested objects. Each layer of the stack may contain one or more object being fabricated. For nested objects, the de-powdering step may be complicated due to, for example, the substantial volume of unbound powder within the entire stack, as compared to an isolated powder print bed associated with only one level of objects, and the relative inaccessibility of objects buried deep within the stack.